273a0c8bc9
AMDGPU is unusual in that the both stack is indexed in the same direction as stack growth (up). We therefore always need the emergency stack slots placed as low as possible to ensure they are in range of load/store instruction immediate offsets. The existing logic is mostly OK, but failed if we required stack realignment. I don't understand what the existing control isFPCloseToIncomingSP is supposed to mean, but can only be used to stop placing the scavenge slots earlier. Make this explicit so that targets can opt-in rather than opt-out only.
127 lines
5.2 KiB
C++
127 lines
5.2 KiB
C++
//===-- SystemZFrameLowering.h - Frame lowering for SystemZ -----*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZFRAMELOWERING_H
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#define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZFRAMELOWERING_H
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#include "MCTargetDesc/SystemZMCTargetDesc.h"
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#include "SystemZInstrBuilder.h"
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#include "SystemZMachineFunctionInfo.h"
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#include "llvm/ADT/IndexedMap.h"
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#include "llvm/CodeGen/TargetFrameLowering.h"
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#include "llvm/Support/TypeSize.h"
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namespace llvm {
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class SystemZTargetMachine;
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class SystemZSubtarget;
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class SystemZFrameLowering : public TargetFrameLowering {
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public:
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SystemZFrameLowering(StackDirection D, Align StackAl, int LAO, Align TransAl,
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bool StackReal);
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static std::unique_ptr<SystemZFrameLowering>
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create(const SystemZSubtarget &STI);
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// Override TargetFrameLowering.
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bool allocateScavengingFrameIndexesNearIncomingSP(
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const MachineFunction &MF) const override {
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// SystemZ wants normal register scavenging slots, as close to the stack or
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// frame pointer as possible.
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// The default implementation assumes an x86-like layout, where the frame
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// pointer is at the opposite end of the frame from the stack pointer.
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// This meant that when frame pointer elimination was disabled,
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// the slots ended up being as close as possible to the incoming
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// stack pointer, which is the opposite of what we want on SystemZ.
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return false;
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}
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bool hasReservedCallFrame(const MachineFunction &MF) const override;
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MachineBasicBlock::iterator
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eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI) const override;
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};
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class SystemZELFFrameLowering : public SystemZFrameLowering {
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IndexedMap<unsigned> RegSpillOffsets;
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public:
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SystemZELFFrameLowering();
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// Override TargetFrameLowering.
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bool
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assignCalleeSavedSpillSlots(MachineFunction &MF,
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const TargetRegisterInfo *TRI,
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std::vector<CalleeSavedInfo> &CSI) const override;
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void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
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RegScavenger *RS) const override;
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bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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ArrayRef<CalleeSavedInfo> CSI,
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const TargetRegisterInfo *TRI) const override;
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bool
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restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBII,
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MutableArrayRef<CalleeSavedInfo> CSI,
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const TargetRegisterInfo *TRI) const override;
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void processFunctionBeforeFrameFinalized(MachineFunction &MF,
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RegScavenger *RS) const override;
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void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
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void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
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void inlineStackProbe(MachineFunction &MF,
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MachineBasicBlock &PrologMBB) const override;
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bool hasFP(const MachineFunction &MF) const override;
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StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
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Register &FrameReg) const override;
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// Return the byte offset from the incoming stack pointer of Reg's
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// ABI-defined save slot. Return 0 if no slot is defined for Reg. Adjust
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// the offset in case MF has packed-stack.
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unsigned getRegSpillOffset(MachineFunction &MF, Register Reg) const;
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bool usePackedStack(MachineFunction &MF) const;
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// Return the offset of the backchain.
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unsigned getBackchainOffset(MachineFunction &MF) const {
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// The back chain is stored topmost with packed-stack.
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return usePackedStack(MF) ? SystemZMC::ELFCallFrameSize - 8 : 0;
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}
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// Get or create the frame index of where the old frame pointer is stored.
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int getOrCreateFramePointerSaveIndex(MachineFunction &MF) const;
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};
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class SystemZXPLINKFrameLowering : public SystemZFrameLowering {
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IndexedMap<unsigned> RegSpillOffsets;
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public:
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SystemZXPLINKFrameLowering();
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bool
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assignCalleeSavedSpillSlots(MachineFunction &MF,
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const TargetRegisterInfo *TRI,
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std::vector<CalleeSavedInfo> &CSI) const override;
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void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
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RegScavenger *RS) const override;
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bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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ArrayRef<CalleeSavedInfo> CSI,
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const TargetRegisterInfo *TRI) const override;
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void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
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void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
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bool hasFP(const MachineFunction &MF) const override;
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};
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} // end namespace llvm
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#endif
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